The field of the invention relates to the entry of characters, including natural language text, into a computer, particularly a miniature handheld personal digital assistant. More specifically, it relates to a method for improving the efficiency of the entry of text and other character sequences by selecting ambiguous combinations of characters and then later disambiguating them to enter words.
As electronic devices get smaller and become increasingly powerful and capable of operation with more flexibility (by, for example, wireless connection to the World Wide Web), there is an increasing need for ways of entering information into miniature handheld devices. Such devices include personal digital assistants, two-way pagers, Web browsers, and the like. They have been described as applying to various platforms, including wristwatches, credit card-sized personal digital assistants, and larger handheld devices such as MP3 music players.
The space available for input on such devices is typically very limited. In cellular telephones, the dialpad has been used for entering text, with some scheme used to indicate which letter is actually desired, given that each key is ambiguous (the xe2x80x9c2xe2x80x9d key, for example, represents either xe2x80x9cAxe2x80x9d, xe2x80x9cBxe2x80x9d, or xe2x80x9cCxe2x80x9d). One scheme requires the user to press the key a certain number of times, thus once to enter an xe2x80x9cAxe2x80x9d, twice to enter a xe2x80x9cBxe2x80x9d, or three times to enter a xe2x80x9cCxe2x80x9d. Another scheme, which has been introduced commercially by Tegic Communications (known as xe2x80x9cT9xe2x80x9d) and others, uses a dictionary and software that allows input of a sequence of ambiguous keys and then displays those words that are consistent with the given input, allowing a user to select the desired word from a menu.
The latter scheme is applicable not only to actual physical keys, but to virtual keys that may be defined on a screen and selected with a stylus or other pointing device. The advantage of the use of the scheme for virtual keys is that text entry is often easier than for a full virtual keyboard because the virtual keys can be bigger, leading to fewer errors, and can use less of the area of the display.
This scheme can also be applied to devices smaller than cellular telephones and that have many less keys (real or virtual) than the eight keys used in a cellular telephone to enter text. However, as the number of keys gets smaller, the chances increase that the user must enter a very long sequence of keystrokes before the desired word is displayed, or even that the desired word will never be displayed. Even with the cellular telephone, as the number of words in the dictionary increases, substantial inefficiencies can result because of cases in which creating a sequence of ambiguous designations turns out to be a poor way of indicating a desired word. It is desirable to develop methods that can reduce such inefficiencies.
The goal of the invention disclosed here is to improve the efficiency of systems for entering information into a computer system based on the entry of sequences of ambiguous items. Each ambiguous item represents one of several possible items, with the actual item entered resolved at a later time.
In such a system, the user typically enters a sequence of ambiguous items and the system determines a list of objects that the user intends, with the objects identified by the sequence of items. These objects are then displayed, and the user selects the intended object, thus removing the ambiguity. Alphabetic text, for example, is entered by selecting sequences of characters to form words. In the present invention, this is done by defining menu items such that each item contains two or more alphabetic letters. Thus, for example, the entire English A-Z alphabet might be represented by 9 menu items, with 8 of the items containing three letters each and the 9th item containing two letters.
Users enter words by selecting a sequence of menu items that each contain the desired sequence of letters. After each selection of a menu item, words are retrieved from the memory that are consistent with the sequence entered so far. These words are added to the menu and displayed. When the user sees the word that is desired, he or she moves the thumbwheel so as to designate the desired word, and presses the button to cause it to be selected. The word is then entered.
In the present invention, the efficiency of the system is improved in cases in which resolving the ambiguity for a particular item will reduce the number of possible objects more than entering an additional ambiguous item. When an ambiguous item is entered, a calculation is made of the extent to which resolving the ambiguity for any of the items entered will reduce that number of possible objects, and, if so, that fact is displayed along with, typically, the position involved.
The system is typically used to enter text into a computer system, in which case the ambiguous items comprise a set of two or more letters, and the intended objects are sequences of letters, typically words in a natural language. Other sequences of letters and characters can also be used, and the resulting objects may be Web addresses, electronic mail addresses, or other objects.
The computer system involved is typically that contained in a handheld or desktop device that contains a relatively small keyboard. Such devices include cellular telephones, two-way pagers, Web tablets, personal digital assistants, cordless telephones, and the like.
The keyboard used to select ambiguous items may be composed of real, physical keys, such as the keys used for dialing a cellular telephone that typically are labeled with digits, but that also have an alternative labeling with several letters of the alphabet (e.g., xe2x80x9cABCxe2x80x9d associated with the key labeled xe2x80x9c2xe2x80x9d).
The keyboard may also be a virtual keyboard, with the items displayed on a display device such as a liquid crystal display or cathode ray tube. A pointing device such as a mouse, trackball, touchpad, thumbwheel, or head-mounted device may be used to select an ambiguous or unambiguous item for entry.
Typically, the system displays not only the information about whether disambiguating a letter position will improve the efficiency of entry, but the particular position (letter position in a word, if that is what is being entered) and the level of efficiency. The system may be biased such that the information is only displayed if the increase in efficiency is above a given threshold, so as to prevent the user having to take the additional effort to perform such disambiguation if the result is only a small gain in efficiency.
The system is also applicable to the entry of electronic mail and Web addresses that contain special characters, in which case xe2x80x9clettersxe2x80x9d are not just the alphabet and xe2x80x9cwordsxe2x80x9d are not necessarily natural language words or names but any sequence of characters defined in the internal dictionary of the system.